Abstract 3262: Alternative strategies of screening and surveillance of patients with Von-Hippel Lindau syndrome to reduce radiation exposure and potential subsequent cancer risk

Abstract

Abstract Background: Von-Hippel Lindau (VHL) syndrome is a rare genetic disorder that predisposes individuals to benign and malignant tumors, including pancreatic neuroendocrine tumors and renal cell carcinoma. Guidelines recommend abdominal Computed Tomography (CT) scans to be performed every one or two years starting in adolescence or young adulthood for screening or surveillance for these tumors. Objective: To assess radiation exposures resulting from alternative strategies of screening and surveillance by abdominal CT scans, and projecting potential cancer risks subsequent to these exposures. Methods: Organ radiation doses were estimated using a dedicated computational solution for CT dosimetry, on the basis of protocols routinely used at one U.S. cancer research center in 2012-2015. Subsequent Lifetime Attributable Risks (LARs) of cancer incidence were projected for lifelong nonsmokers, using a dedicated radiation risk assessment tool and accounting for the reduced life expectancy of individuals diagnosed with VHL. We assumed additive effects between VHL gene mutation and radiation exposures. Results: Based on a standard CT protocol, annual scans over a lifetime starting at age 15 are associated with cumulative colon doses of 1.8 Gy at age 30, 3.8 Gy at age 50. The associated LARs of cancer incidence would be 1–2% at age 50, and 11–32% at age 80. Delaying age at screening start to 21 years would reduce the projected risks to <1% at age 50 and <15% at age 80. A frequency of one scan every two years (as used for surveillance of cystic pancreatic lesions) would be associated with LARs of <1% at age 50 and <10% at age 80. The current use of a new CT protocol (dual energy virtual non-contrast CT) at the department would reduce radiation exposures and potential subsequent risks by more than 50%. Conclusion: Annual CT screening and surveillance for pancreatic and renal tumors in VHL patients can be associated with high radiation exposures. When Magnetic Resonance Imaging is not appropriate as an alternative imaging technique, delaying age at surveillance start or reducing the frequency of CT scans could significantly reduce the potential radiation-related risks, provided that these strategies remain beneficial for patients. Optimized CT protocols can also dramatically reduce radiation exposures. The present study is currently extended to confirm our dose estimates based on CT protocols against individual radiology data, and consider other genetic syndromes. Ultimately, this study should help defining surveillance strategies with optimal risk-benefit balance. Citation Format: Neige MY Journy. Alternative strategies of screening and surveillance of patients with Von-Hippel Lindau syndrome to reduce radiation exposure and potential subsequent cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3262. doi:10.1158/1538-7445.AM2017-3262